Online input-lag - Lan adapter Solution?

[Eaglejim]

Hello fellow smashers
After playing around 30 online 1v1 matches, I'm getting really mad..
I've got input lags of 0.5-2 secs in every match, even when I'm playing with a friend in the same city.
He claims he has no lags, but i think he just doesn't notice them like most players (example: tv mode not set to gaming -> always input lag -> what lag?-.-)
When I'm playing local with my friends I have no problems at all reacting to their rolls, countering, evading etc, while online I can't even sh nair ff, the game just doesn't get it, even if I try to buffer the inputs (teching doesn't work at all) - no chance
I got no problems with other games for example bf4 (Ping of 15).
My connection (down- & upload) is fine.

Could a lan adapter work on this problem?
Tried to connect via 4g tethering -> no matches found.
What else could I try?
Are you experiencing the same problems?

Its the first game I play online using wifi (why doesnt the wii u have a lan port??!!)

(Sorry for my bad english, still learning it^^'')

Edit: If I should buy an adapter, which one would it be?

 

[genesis_SOC]

Having a lan adapter won't help you if your internet sucks, which it sounds more like the case. I play on wireless and the majority of my matches have very little input lag, no where near 0.5-2 seconds.

 

[xPROFx]

LAN adapter will help only if problem caused by WI-FI connection. If its stable, try open all ports on your router for wiiu. P.S. wiiu supports only wii-lan adapter

 

[Eaglejim]

I've got a 100mbit/s connection and most of the time a ping of 15, so it should(!) not be caused by me in general.
Parts of it could be because I live in Switzerland and play often vs. americans. Even matches against people from France and UK lag like all others, which definitely should not be.